This page is currently under construction. Further description of the Big Thompson and a process domain map will be included at a later time.
Big Thompson Watershed
Big Thompson River Drainage Basin
Big Thompson River in Rocky Mountain National Park
(Photo by E. Wohl)
The Big Thompson River begins at an elevation of 3447 m in Rocky Mountain National Park. It joins the South Platte River about 8 km south of Greeley, draining about 2300 km2. The river was named for 19th-century fur trapper David Thompson and once had abundant beaver. Today the river below Rocky Mountain National Park is highly regulated and is part of the Colorado-Big Thompson Project, a massive diversion from the headwaters of the Colorado River via a tunnel beneath the Continental Divide that joins the Big Thompson just downstream from Estes Park.